Gearbox oil question

["Ken Davis" <ken.davis@attbi.com>]

Hi List,

Now that I'm back running, I've started to check and change the vital fluids.
The gearbox/J-OD is just fractionally low, and, as I was getting ready to pump
in a 1/2 pint, I read the container -- its a valvoline 85-90, but it's GL5.
Recall having read that GL5 is not good, bad for synchro (?).   Is it?  Should
I drain, flush and refill ( I have oodles of time on my hands), and short of a
GL4 refill, I hear mention that 20W50 motor oil is also a good bet?
Comments?


Thanks

Ken
SSF
73 '6, CF7000U0